2,5-Dicarbazole-functioned siloles with aggregation-enhanced emission for application in organic light-emitting diodes

2,3,4,5-Tetraarylsiloles are efficient solid-state luminescent materials with good electron-transporting ability. Substitution at the 2,5-positions of silole rings produce various outstanding functional materials that can be used as active layers in organic light-emitting diodes (OLEDs). In this work, two 2,5-dicarbazole-substitued siloles, (2-Cz)₂MTPS and (3-Cz)₂MTPS, are facilely synthesized and fully characterized. Their thermal, photophysical, electrochemical, and electroluminescent properties are investigated systematically. The results show that these 2,5-dicarbazole-functined siloles are thermally stable and feature aggregation-enhanced emission characteristics with high solid-state photoluminescence efficiencies. Nondoped OLEDs [ITO/N,N′-di(1-naphthyl)-N,N′-diphenyl-benzidine (NPB) (60 nm)/emitter (20 nm)/TPBi (40 nm)/LiF (1 nm)/Al (100 nm)] fabricated by adopting (2-Cz)₂MTPS and (3-Cz)₂MTPS as light-emitting layers exhibit good performances, with high luminance of 28240 cd m^-2 and electroluminescence efficiency of 4.5 cd A^-1.